Suicide and Seizures: A National Cohort Study in Veterans

Background: The increased rate of suicide associated with epilepsy has been described, but no studies have reported the rates of suicide and suicide related behavior (SRB) associated with psychogenic non-epileptic seizures (PNES).

Methods: This retrospective cohort study analyzed data from October 2002 to October 2017 within Veterans Health Administration (VHA) services. Of 801,734 veterans, 0.09% had PNES, 1.37% had epilepsy, and 98.5% had no documented seizures. Veterans coded for completed suicide, suicide attempts, and suicidal ideation were identified from electronic health records (EHR). The primary measure was the suicide-specific standardized mortality ratio (SMR) based on the number of suicide deaths and CDC national suicide mortality database. A Poisson regression was used to calculate the relative risk of suicide across groups.

Results: A total of 1,870 veterans (mean age [SD] 33.76 [7.81] years) completed suicide. Veterans with PNES (RR = 1.75, 95% CI 0.84-4.24) and veterans with epilepsy (RR = 2.19, 95% CI 2.10-2.28) had higher risk for suicide compared to general veteran population. Veterans with PNES or epilepsy had higher risk of suicide and SRB if they had comorbid alcohol abuse, illicit drug abuse, major depression, post-traumatic stress disorder (PTSD), and use of psychotropic medications. Conversely, those who were married or attained higher education were at decreased risk. The SMR for completed suicide for PNES, epilepsy, and the comparison group was 2.65 (95% CI 1.95-5.52), 2.04 (95% CI 1.60 - 2.55), and 0.70 (95% CI 0.67 - 0.74), respectively.

Conclusions: Veterans with seizures (both psychogenic and epileptic) are at an increased risk for death by suicide and SRB than the comparison group. These findings suggest that while the pathophysiology of PNES and epilepsy are different, the negative impact of seizures is evident in the psychosocial outcomes in both groups.